Irrigating solutions are widely used in intraocular surgical procedures, such as phacoemulsification, vitrectomy surgery and glaucoma surgery. Phacoemulsification is a surgery to remove the lens of the eye that has developed an opacification, which is referred to as a cataract. Vitrectomy is a surgery to remove some or all of the vitreous humor from an eye. Glaucoma surgery is associated with a laser treatment or making a cut in the eye to reduce the intraocular pressure. In Taiwan, according to a report of National Health Insurance Department about 150,000 ocular surgical procedures were performed annually. The effect of intraocular surgery is related to the irrigating solution used. An improper irrigating solution may cause damages to cornea or lens, resulting in poor vision, blind spots and even loss of vision.
A desired irrigating solution is supposed to have a composition that is close to aqueous humor and an osmolarity of between 290 mOsm and 320 mOsm. The major function of irrigating solutions is for maintaining endothelium cell integrity, corneal thickness and retinal tissue. Moreover, an appropriate irrigating solution should preserve the viability of corneal endothelial cells during cataract surgery, provide an energy source (i.e., glucose), maintain appropriate tonicity and electrolyte concentration, and protect corneal endothelium cells from fluctuation of pH value.
Balanced Salt Solution (BSS®) and BSS PLUS® have been frequently used for intraocular irrigation. The composition of BSS PLUS® is dose to that of the aqueous humor. Basically, the composition of BSS PLUS® has four parts: 1) adequate buffer (i.e., bicarbonate), 2) energy source (i.e., glucose). 3) stable pH value between 7 and 8 (i.e., HEPES). 4) antioxidant agent (i.e., glutathione) However, these intraocular irrigating solutions are not effective enough to protect corneal (endothelial) cells, which are most liable to sustain physical damage in ophthalmic operations. Studies have indicated that a sophisticated intraocular surgery, such as phacoemulsification, may cause potential complications. Some possible reasons for causing complications include the mechanical effects of ultrasound, physical trauma caused by nonaspirated lens fragments, heat production and even osmotic irregularities caused by the irrigating solution. All of these may result in damages to corneal endothelium and even may have the risk of leading to irreversible bullous keratopathy.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies, especially in connection with development of ocular irrigating solutions with an improved functionality to protect intraocular tissues, particularly conical (endothelial) cells.